A number of pump controls have been proposed for controlling the pumping of oil wells so that when the wells "pump off" or "pump dry", that is do not pump liquid, the pump is stopped as there is a considerable amount of added expense or cost per barrel of coil pumped when no oil is being produced. Also, pumping dry wears out downhole pumps, sucker rods, uses more electricity and the like, and wears out packing around the sucker rods thus causing leakage of oil and gas to the atmosphere and surrounding environment.
These prior pump control systems have not been entirely satisfactory in that many of them simply monitor what the pump is doing and are adversely affected by the geometry of the pump parts, many are affected by surges or flow of gas, others utilize a sensing device which do not always distinguish between oil and gas, which is affected by wet gas, paraffin and other solids build-up, and the like. Also, many of these pump controls are complicated, expensive, require extensive modifications to well pumping installations and are not reliable in operation for various well pumping conditions. Those prior pump controls which do not effectively stop the pump when it pumps off causes undue wear on the packing causing leakage of oil and gas to the atmosphere and surrounding environment. Various of the foregoing proposals for pump controls are illustrated and described in the following U.S. Pat. Nos. 2,316,494; 2,456,456; 2,550,093; 2,741,986; 3,091,179; 3,274,940; 3,299,817; and 3,549,276.
It would be highly advantageous to provide a relatively simple, inexpensive and reliable pump control which monitors the liquid being pumped and acts in response thereto for controlling the pump, which is unaffected by flow or surges of gas, wet or dry, and which can be installed in existing pumping installations with a minimum of modification or adaptation. The present invention is directed to such a pump control.
Accordingly, it is an object of the present invention to provide a pump control for a pump driven by an electric motor which controls the pump in response to liquid being pumped, which is unaffected by flow or surges of gas, wet or dry, and does not act in response to the pumping action of the pump.
A further object of the present invention is the provision of such a pump control which does not utilize a sensor which is adversely affected by paraffin or other solid build-up, vibration, moisture, gas and the like.
Yet a further object of the present invention is the provision of a pump control for controlling an electric motor-driven pump for pumping oil from a well through a horizontal discharge line, which may be attached to and supported by the discharge line with a minimum of modification or adaptation of existing well installations, and which may be used with either a horizontally-disposed or a vertically-disposed check valve downstream of the pump control.
Yet a further object of the present invention is the provision of a pump control which automatically stops the pump after it has pumped off thereby minimizing wear on the packing at the well head about the string of sucker rods thereby minimizing leakage of oil and gas to the atmosphere and surrounding environment.
A still further object of the present invention is the provision of a relatively inexpensive and reliable float control which may be readily attached to and installed on normal well-pumping installations with a minimum of adaptation and expense.
A still further object of the present invention is the provision of such a well control including a float assembly having a float located out of and shielded from the direct inflow of fluid into the float chamber thereby preventing the direct inlet flow adversely affecting movement of the float with changes in the liquid level.
Yet a further object of the present invention is the provision of such a pump control which may be readily and easily installed with a minimum of adaptation on the horizontal portion of the discharge line of a typical pump installation.
Yet a further object of the present invention is the provision of such a pump control having a time delay which functions after loss of fluid from the well to keep the pump operating for a short period of time thus guarding against pump shut off due to a temporary loss of liquid from the well and allowing the additional pumping action to clear the liquid from the float chamber through a drain line thereby causing the float to be lowered and to actuate a switch to shut off the pump.
Other and further objects, features and advantages will appear from the following summary, brief description of the drawing, description of presently-preferred embodiments and the claimed subject matter.